Delta Ursae Minoris (δ UMi, δ Ursae Minoris; also 23 UMi) is a star in the constellationUrsa Minor. It has the traditional name Yildun (also spelled Vildiur, Jildun, Gildun, and Yilduz), from the Turkishyıldız "star". It may also[citation needed] have been called Pherkard, an alternate spelling of Pherkad, used for γ UMi and 11 UMi.

The star is mentioned in the Honorverse, a series of military science fiction novels written by David Weber, as the headquarters of Technodyne Industries of Yildun, a major Solarian League shipbuilding corporation with rather questionable ethics (e.g. business ties with Manpower Incorporated and Jessyk Combine, both of Mesa), though the star system is described as including only a (highly mineral-and-metals-rich) asteroid belt.